The proposed research will examine the impact of several inter-related aspects of neighborhood context on both physiological parameters (i.e. biomarkers of allostatic load) and health outcomes. We will examine many of the neighborhood characteristics considered most important in structuring individual lives and thereby affecting health outcomes including: neighborhood socio-economic status, social structures, and neighborhood quality. Using NHANES data merged with Census data and commercially obtained census-level characteristics, and measures developed in the data core, the proposed research will explore how neighborhood context affects and interacts with individual behavior and biology to determine health and disease. We will examine the impact of the built and social environment on racial/ethnic and income disparities in health, with a particular focus on the ways in which the immediate physical surroundings of neighborhoods affect and interact with individual level structure and process to generate health disparities. Multilevel modeling will be used to test hypotheses, controlling for individual-level sociodemographic variables. A clear understanding of the contributions of neighborhood characteristics to individual health and to health disparities may provide targets for intervention to reduce health disparities and improve health in vulnerable populations. Identifying the relevant social and biological pathways will enable us to develop and refine a conceptual model that we can use to identify more effective and equitable health improvement efforts.